My atomic wall clock loses time?

Get a watch.

All clocks depend on some physical property that has some kind of rhythm or regular action. A pendulum is an example. In a mechanical watch a spring and wheel oscillate one way then the other. The rest of the clock simply counts the number of times the regulator acts and displays the outcome. For a long time the rotation of the earth was considered the standard for keeping time. As technology progressed the vibration of quartz crystals became a superior regulator for a couple of good reasons the vibrations produced an electrical signal and the material is very stable so the regulation is quite accurate. Technology has progressed even further and it was discovered that certain materials vibrate (for want of a better term) at the atomic level with even better regularity. Clocks that use this atomic vibration are called atomic clocks. These clocks are very accurate. The Federal government operates some of the most accurate of these clocks and broadcasts the time over the airwaves. The clocks you can buy at the drugstore are really quartz regulated clocks that are periodically checked against the broadcast signal and reset as needed. Mine checks once every day.

On the positive side they are 100% correct twice a day!

If they are within the gurantee period, first of all speak to the supplier.

If not, then speak to the manufacturer.

If they are of doubtful pedigree and come from the honourable Far East I would scrap them.

I would throw them away and get a new clock that give out the right time